The C2BGAs are fabricated using a complicated etching donut isolation method, resulting in copper islands on the core that are suspended by some isolation material, and then followed by surface processing and photo via steps. The incurred cost for the complex steps and the resulting complex structure is significant.
The Ball Grid Array (BGA) is an advanced array package for fine pitch, high pin count semiconductor packaging, which is used normally in a multiple-layer chip-up printed wiring board (PWB) substrate for housing the integrated circuit structure in today""s IC industry. However, the heat dissipation is a major concern with the arrival of high speed CPUs such as the Pentium II and III, as well as high speed graphics, networking, DSP, and programmable logic chips. Better thermal BGA packaging solutions are required to fulfill the need of IC products in the 21 century.
The object of this invention is to provide a new and simpler PWB structure and method with comparable or better thermal performance, resulting in lower cost and better reliability. High degree of flexibility in choice of material and layer counts and layer thickness allows for a wide range of applications in packaging and high density printed circuit board or PWB. The plated copper vias also allow for better thermal performance and result in better overall thermal performance for the resulting package.
The processing steps are also ones that have proven to be practical for implementing high density interconnect for packaging applications.